1. Field of the Invention
Embodiments relate to a hardmask composition for lithography, the hardmask composition including one or more aromatic ring-containing polymers with a strong absorption in the short wavelength region (e.g., 157 nm, 193 nm, and 248 nm), and a method of patterning material on a substrate using the same.
2. Description of the Related Art
There is a continuous demand to reduce the size of structural shapes in the microelectronics industry and other related industries, including the manufacture of microscopic structures, e.g., micromachines, microelectromechanical systems (MEMS), and magneto-resistive heads. In the microelectronics industry, there exists a need to reduce the size of microelectronic devices in order to provide a number of circuits in a given chip size.
Effective lithographic techniques are essential to achieve a reduction in the size of structural shapes. Lithography affects the manufacture of microscopic structures from the viewpoint of direct imaging of patterns on particular substrates and production of masks typically used for such imaging.
For better resolution in most lithographic processes, an antireflective coating (ARC) is used to minimize the reflectivity between an imaging layer, e.g., a radiation-sensitive resist material layer, and an underlying layer. However, since many portions of the imaging layer are removed during etching of the ARC after patterning, patterning may be further required in the subsequent etching operation. That is, in some lithographic imaging processes, the resist does not provide resistance to the subsequent etching operation to an extent sufficient to effectively transfer the desired pattern to a layer underlying the resist.
In the case where an extremely thin resist layer is required, an underlying material to be etched is thick, a large etching depth is needed, and/or the use of a particular etchant is required depending on the type of an underlying material, a so-called ‘hardmask layer’ may be used as an intermediate layer between the patterned resist layer and the underlying material that can be patterned by transfer from the patterned resist. The hardmask layer should be able to receive the pattern from the patterned resist layer and withstand etching required to transfer the pattern to the underlying material.
Conventional hardmask materials are difficult to apply to substrates. Accordingly, the use of chemical and physical vapor deposition, special solvents, and/or high-temperature baking may be required. However, these methods not only necessitate the use of expensive equipment or the introduction of advanced techniques but also involve relatively complicated processes, thus incurring considerable production costs of devices. Thus, a hardmask composition that can be applied by spin-coating techniques would be desirable. A hardmask composition that can be selectively etched using an overlying photoresist layer as a mask in an easy manner while being resistant to etching necessary to pattern an underlying metal or silicon compound layer using a hardmask layer as a hardmask, would also be desirable. A hardmask composition that provides superior storage properties and avoids unwanted interaction with an imaging resist layer, e.g., avoids acid contamination from the hardmask, would further be desirable. A hardmask composition that has particular optical properties against imaging radiation at shorter wavelengths (e.g., 157 nm, 193 nm, and 248 nm) would also be desirable.
Numerous technical difficulties remain in patterning relatively thick underlying layers by dry etching. For example, an overlying hardmask layer formed by spin coating may have an isotropic, e.g., bowed, etch profile during dry etching, which makes it difficult to allow the hardmask layer to function as a hardmask of a relatively thick underlying layer. Attempts have been made to prevent the occurrence of isotropic etch profiles, for example, by varying dry etching conditions. However, device makers suffer from limitations in the operation of mass-production facilities. Accordingly, there is a need for advances in hardmask composition technology.